Compact Groups in the SDSS

DÍAZ, E.; RAGONE, C.; MURIEL, H.; ZANDIVAREZ, A.

Pucon, Chile

Congreso; XI IAU Regional Latin American Meeting of Astronomy; 2006

IAU

We identify compact groups in the Sloan Digital Sky Survey (SDSS) using an algorithm similar to that developed by Lee et al. (2003, astro-ph 0312553). Given that some authors claim compact groups to be chance alignments of galaxies or diffuse galaxy groups cores (Zandivarez et al. 2003, MNRAS, 340, 1400), our intention is to make a statistical study of the amount of compact groups that are real entities. To do so, we construct mock catalogues of the SDSS from cosmological numerical N-body simulations and identify compact groups with the previous algorithm. Next we compare them with groups identified with a tree-dimensional algorithm similar to the friend of-friends algorithm developed by Huchra & Geller (1982, ApJ, 257, 423).